Boom



G. HOLMES July 20 1926.

BOOM

July 2o, 1926. 1,593,261

G. HOLMES BOOM Filed July 30. 1923 5 Sheets-Sheet- 2 Hmmmv IIIH G Home@ July 20, 1926. y Y G. -HQLMEs v 1593261v BOOM Filed July 3o, 192:5 v s sneets-shet s' lullin, Wm'

GRANT HOLMES.

llatented duly 20, 1926.

UNETE STATES GRANT HOLMES, OF EANVILLE, ILLlNQS,

ASSGNR TO THE MARON STEAM SZIOVEL COMPANY, OF MARION, OHIO, A CORSGRATQN F QHO.

j i o BOOM.

Application filed July 30, 192,3. Serial No. 654,568.

This invention relates to booms and is designed more particularly for use in connection with power shovels of the revolving type.

One object oit the invention is to provide a boom ot' great strength; and, tuii'ther, to provide such a boom which will be ot relatively light weight as compared with its strength; and which can be produced at a relatively low cost.

'Rotary power shovels as constructed in the past have ior the most part comprised a rotary trame on which the boom was mounted, the toot ot the boom usually resting in a socket or between ears at the trout end ot the trame and extending upwardly and forwardly at an angle of about forty live degrees. The boom is held in this position by suspension from the point thereot by means of cables or hog rods extending trom the boom to a gantry., or A trame, mounted on the revolving trame and braced or stiftened by means of a bridge, which bridge also provides a high point for coni'iecting the cables or hog rods. rlhe boom itseltl is usually heavier, or of greater size1 near the center thereof and the upper and lower sides or edges thereof converge torwardly and rear"wardly, The shipper shatt and crowding engine are mounted en this heavier portion oi the boom and the dipper handle extends through the boom adjacent to the shipper shaft. When a machine ot this character is not working and the dipper is resting on the ground the boom is subject to certain strains, the under side ot the boom being` under tension and the upper side ot the boom being in compression. Then the dipper is raised oit the ground these strains are proportionately increased, it being understood that in the larger types et shovels these dippers are oi". large size and even when empty impose a heavy load on the boom. When the clipper is crowded into the tace of the banlr, upon which it is working, a backward thrustA is exerted through the flipper handle and shipper shaft and this thrust serves to reverse the strainsiniposed upon the boom, the lower side the boom being placed under compression and the upper side of the boom being placed under tension. After the dipper has finished its cut andthe weight ot the 'loaded clipper iinrosed, @n the been the Strains ,are again 1f@- yersed, bringing. the `lower side kot the 'hoorn under tension and the upper side under compression. lt will be understood that in the operation ot' the shovel this reversal of the strains takes place at frequent intervals and is highly destructive ot' the boom. As has been stated .most booms of this character are heavier adjacent to the shipper shaft, but the portion of the boom between the shipper shaft and the point Ais subjected to these constantly reversing strains with the result that it gradually weakened to the breaking point. Further, the swinging of the loaded dipper imposes a very severe twisting strain on the lower or toot portion ot the boom, which is smaller in section, usually about oue-third ot the distance from the toot of the boom to the shipper shaft, and this strain gradually weakens this portion of the boom to the breaking point. These strains are present in all booms of this character but they become more pronounced in the larger size machines and it has been tound impractical to increase the size and strength of a boom ot this kind sui'liciently to overcome the destructive action ot the strains upon the boom.

A. further object of the invention is to so construct the boom that these reversing strains will be reduced to such a degree that they will not be serious. To accomplish this it is also'an object ot the invention to provide a boom structure in which the boom will be integral with the rotating trame.

i A further object of' the invention is to provide such a boom structure which may be built largely of plates, which not only enable it to be produced at a low cost but provide a very large degree of strength in proportion to their weight.

Other objects ot the invention will appear the device is described in detail. y

.In the accompanying drawings Fig. l is a side elevation of a rotary steam shovel em-A bodying my invention; 2 is a top plan view ol the same: Fig. 3 is a. section taken on the linem oit Fig. l; Fig. i is a section taken on the line 4 4 of Fig. l; Fig. 5 is a bottoni plan view of the boom structure; Fig. 6 is a longitudinal sectional viewot the boom structure .and platform; and Fig. 'l' is a sectional view taken on the line'T--T oit Fig. 1.

In th Le drawings l have illustrated one einliodi nt et my invention hate shown the saine as applied tov av rotary power shovel of large size, such as are commonly used for stripping,- the over-burden from surface deposits of coal and ore. Shovels of this type are of very large sise, many of them employing a boom 90 feet in length with a clipper having capacity of eight cubic yards, and it will be apparent that a very heavy load is imposed upon the boom. Beca-use of the weaknesses which develop in these booms, as above set forth, it has been found impractical to extend the length of the boom or the capacity of the clipper beyond those stated.

The steam shovel here shown conugriffies` a base 1 which is mounted on suitable traction devices, such as trucks i?, and carries a platform 3, which is mounted on the baie for rotation about a vertical axis, as shown at 4. rthis platform carries the power plant and the operating and controlling machinery for the excavating inechanisi'n. ln ap. plyingl my invention to such a shovel l. mount en the revolvingv platfrom a frame which extends upwardly therefrom and is rigidly secured thereto. R' idly secured to this frame and preferably 'formed integral therewith is the boom proper which entends upwardly and forwardly from the frame and which tapers from the frame to the point of the boom. The frame extends lengthwise of the revolving platform and is secured thereto bot-h in front of ard in the rear of the axis of rotation and inasmuch as this frame constitutes a part of the brom r structure it will be apparent that the boom itself rotates about a vertical axis extending; through the lower portion thereofv The boom structure may be constructed in various ways but l prefer to build the saine from metal plates connected together and reinforced by such angles, channel beams and the like as may be necessary. llo this end l have` in the present embodiuicnt of mv invention` formed the frame portion of the boom structure from two upriejbt plates 5 extendingr lengthwise of the platforni and rigidly secured thereto in any suitable marier, as by means of angles o. ln the present instance, these frame meinbers or plates 5 are triangular in shape and extend for the full length of the platforn'i, the apex of the angle being' arranged adiacent to the artis of rotation of the platform so as to provide the highest part of the frame at this point. lt will be obvious. howeverx that the frame members maytalie various'shapes and tl it is not esential that they siould extend for the full lena h of the platform. The plates are preferaely reinforced or stiffened, as by securing thereto transverse bars or angles 7. Further, the plates are braced and held rigidly in their upright positions by means brace bars 8. preferably angle bars, rigidly secured at their` lower ends to the plat-form s raadsel and connected at their upper ends with the upper edges of the respective plates 5 by means of top plates 9 which are rigidly connected both to the brace bars and the frame members and are preferably reinforced with angle irons. If desired, bulhheads El, formed of plates or bars, may be interposed between the reinforcing bars 7 and the brace bars 8 to further stii'ifen the struct-ure. The frame members or plates 5 are spaced a considerable distance apart and, in the present instance, are spaced short distances from the respective lateral edges of the platform. These plates may, if desired, form a part of the housing 10 vithin which the power plant and operating mechanism are arranged.

Extending forwardly from the edges of the respective frame members or plates are two forwardly convering plates 11 which are rigidly connected at their rear edges with the forward edges of the resilioctive frame plates, preferably by rivetii so to form in effect an integral part fr. ne structure. The forward ends of these converging' plates are spaced short distances apart, and rigidly connected with the respective forward edges thereof are other platos 12 which extend forwardly and upwardly there'l'ron'i, these plates also being secured to the converging plates by means of rivets or the like in such a manner as to fori'n an integral part thereof. The plates l2 are arranged substantially parallel so as to form between them a space through which the clipper handle 13 may extend. lhe converging' plates 11 and the parallel plates 152 are preferably reinforced by transverse :Jingle bars 14% and are braced by up ri= ht brace bars or angles 15 spaced thcrefrom on the outer sides thereof and couuectcd thereto by bottom plates 16 and a top plate 1T. Preferably bulkheads "l5", similar to the bulkheads 8a, are connected with el ch pair et' bars, 14 and 15. to form very rigid braces for the vertical plates. The top plate 17 is of a width equal to the overall width of the boom and is rigidly sccured to the upper edges `of both sets of plates. ll and lf2, and to the brace bars 15 and plates l5 on each side of the boom1 thereby uniting these parts in an integral structure, rlhe bottom plates 1li are separate one from the other so as to provide space between the lower edges of the vertical plates throughout the length of the boom proper The convergino' plates 11 re connected one to the other bv a transverse plate Secured at its lateral edges to the respective coni"ergingplates and, in the pres nl, instance. arranged in a substantially horizontal position. The rear edge of this plate 18 is turned upwardly. as shown at 19, and is ri idly secured to the forward edges of the traine plates 5, thus tying these frame plates together` and reinforcing the traine structure. Anvertical plate 20 entends transversely between the plates 12 adjacent to their points ot connection with the plates 1l. .The top plate 17 is provided near the longitudinal center ot the booin with an opening 21 thiv'ough which the clipper handle 13 entends. Extending downwardly from the rear edge ot the opening 21 to the lower edge of the vertical transverse plate 2O is a transverse tie plate 22. Ei;- tending forwardly troni the forward edge ot the opening- 2l in an approximately liorizontal position isl a transverse plate 2B, and extending troni the forward edge ot the transverse plate 23 upwardly a Stillstantially vertical transverse plate 2l. 'lhc plates 22 23 and 24, are rigidly secured al, their respect-ive edges to the plates 12 and the plates 22 and 23 are so arranged as to provideV an ample space within which the dipper handle n'iay swing. rlhe vertical 'ransverse plate 24 is spaced t'roin the point ot the booin a distance suticient to permit ot the mounting oi the sheaves between the two plates at the point ot the boom. lt will be apparent that by assembling the parts in the manner set forth I have provided a unitary booin structure comprising within itself an integral traine and booni. The upper and lower edges of the plates 11 and 12 converge toward the point ol the boom so as to give the boom a tapered shape troni the 'traine portion thereof to the point thereor. l prefer that the lower edge oi'i the boom shall constitute a straigl-it line troni its point of' connect-ion with its :traine nien'ibcrs lo the point there/ot. lit desired, the upper edge ot the hoorn inay `also constitute a` straight line troni the point oit' the boom. to the rear edge ol2 the traine n'unnbers which, in the present instance, is the rear end ot the platform. However, it is not essential that the upper edge et the booni should be straight and it inay he given any suitable shape. The top plate 18 converges from the traine n'ieinbers to the forward end or joint of the boom so that the lateral sides olf' the boom structure as a whole converge liorwaixlly.

lt will .he apparent that a boein so constructed will have very great strength, and that the pia-tes being arranged on ,edge will provide a relatively large degree ot strength in proportion to their weight. The converging plates extending troni the forward edges ot the widely separated tra-lne plates to the rear edges ot the narrowly separated booin. Plates 'l2 serve` not only to connect the plates 12 of the outer portion of the booni structure with the 'traine members but also to brace the outer portion of the. boom structure against'the traine and thus `resist the strains vianiposed thereon by the swinging oit the load, lt will be noted that these converging plates 11 and the plate 18 are .so arranged that they brace the booni .structure at the point where the swinging strains are the greatest. lt will be understood, oit" course, that the load on the rear portion oit the revolving traine will be sutlic'ient to couuterbalance the forward or booi'n portion of the structure. Ordinarily the weight et the power plant and other mechanisn'i n'iounted on the platform will be sutilcient tor this purpose but obviously additional .veigl'it could be provided il necesy 'llhe hoorn structure as a whole coinpriscs in e'l'lect cantilever construction and the underside ot the boom will always be under compression and'- the upper side ,re-ol' will always be under tension, thereeliminating entirely the reversal of ten-v ;linand compression on the upper and lower edges oli the booni which are so destructive oi" the old type ot boom. Further, in ion the cross sectional area. ot the boon] increases troni the point of the booni to the base or traine portion thereof and this, coupled with the bracing action oli the convereing` plates, 11 and 18, entirely overcomes the` strains iin-posed on the booin hy the swinging of the load.

llot only does this booin sgructure eliminate the destructive strains which were present in the toriner booi'ns but by so doing it inakes it possibleito increase both the length tot the booin and the capacity ol the clipper. Further, the character ot the construction is such that the boom inay be built and assembled at a relatively low cost, `the sheets-being easily 'termed and assei'i'iliiled. Further, the construction is sellisupporting, that is, the forwardly and upwardly extending portion oit the hoorn structure is si'ipported by the 'traine portion thereot without suspending devices ot any kind, and l ain enabled to do away entirely with the sway cables or hog rods, the suspension cables, the A 'traine or gantry, the hridge,'and inany other smaller parts which were essential in the former type ot construction, thcreoy not only further reducing the cost but sin'iplitying the construction ot the machine as a whole and greatly reducing the maintenance cost. lt will be understood that the crowding engine' and its associated parts will be mounted on the upper edge ofthe boom. together with auch other mechanism as may be desirable in the operation ozt the` machine. but these parts 'torni no part of the invention and would add nothing to the disclosure they iave been omitted. The transverse brace plate 18 being arranged in a horizontal position between the converging plates 11, niav conveniently be used as a work door en Eredlich repair wei i be done se.-

Cil

il l) ice rions parts of the mechanism carried by the boom without the necessity of lowering these parts to the ground.

When the boom structure is to be erected in the field the frame will be erected on the revolving platform and the outer portion of the structure, or the boom proper, will be erected on blocks in a substantially horizontal pr-isition and when assembled the lower rear edge of this portion of the boom will be connected with the forward edges of the frame plates 5, or with the frame 3, f a l. fre or pivot pin 27. The boom is ced on its upper edge with a nest of sheaves and a second nest of sheaves 29 is moc ed on the upper edges of the frame plates. rEhe hoisting cable from the main nec-ting engine is litted about the sheaves of the two nests and by the application of power i this cable the boom is raised to its ele 'ated position and may then be rivetsrl or bolted in that position, thereby integrally connecting the boom and the rotating frame into a unitary boom structure.

.i will be understood that, particularly in the er sizes, it will not be practical to form t e several plates of single pieces of metal but that each plate will be built up from a plurality of plates of standard size. lilhile l prefer that the several members herein referred to as cplates shall be in the form of flat plates, in strict meaning of the term, this is not absolutely essential and these members may be of any suitable construction.

lfi'hlle lY have shown and described one embodiment of my invention l wish it to be understood that f do not desire to be limited Lo the details thereof as various modifications may apuear to person skilled in the art.

'il-ivi c new fully described my invention, i claim as new and desire to secure by Leiters Patent, is:

i. l n a machine of the character described, the combination with a revolving platform, of a boom structure having a lower portion comprising side frames mounted on said platform in spaced relation one to the other, extending for sni'istantially the full length of said platform and havingtheir upper edges inclined. up *ardly and forwardly, said boom structure also having an upwardly and for-- wardly extending portion, the upper and lower edges of which converge forwardly, the rear end of the last mentioned portion of said boom structure being of a height substantially equal to theI height of the forward ends of said side frames and being rigidly secured thereto.

ln a. machine of the character described, the combination with a revolving platform, of a boom structure having a lower portion comprising triangular side plates having their lower edges mounted on. said platform in spaced relation one to the other and ett tending for substantially the full length thereof, said boom structure also having an upper portion comprising plates spaced one from the other and rigidly connected one to the other, the last mentioned plates being rigidly secured at their lower rear ends to the forward ends of the respective triangular' plates and having their upper and lower edges converging forwardly therefrom.

3. in a machine of the charatcer described, a revolving platform, an integral boom structure rigidly secured to and wholly supported by said platform, said boom structure having its upper and lower edges converging from said platform toward the point of the I boom, the lower edge of said boom structure terminating adjacent to and being secured to the forward edge of said platform and the ripper edge of .said boom extending to a adjacent to the rear edge of said platl-. ln a machine of the character described, a revolving platform, an integral boom structure rigidly secured to and wholly supported by said platform, said boom structure having straight upper and lower edges converging from said platform toward the point of the bocn'l, `he lower edge of said boom structure terminating adjacent to and being secured to the forward edge of said platform and the upper edge of said boom extending to a point adjacent to the rear edge of ,said platform.

in a machine of the character dcscribed, a revolving platform, and a. self supporting inclined boom structure having the lower end portion thereof resting upon and rigidly secured to said platform and extending lengthwise thereof from a transverse line in front of its axis of rotation to a transverse line in the rear of said axis, the lower edge of said structure terminating adjacent to said platform.

6. An integral boom structure having a lower portion constituting a supporting base, and an upper portion constituting a boom arm, said base comprisinide frames rigidly mounted in spaced rela on one to the other, said boom arm comprising menr bers spaced one from the other a disfitanre less than the distance between said side frames, rigidly connected one to the other and having forwardlj` and upwardly converging upper and lower edges, and means for connecting the rear ends of the menibers of said boom arm with the forward ends of the respective side frames and for brac said boom arm against said side frames to resist lateral strains on said boom arm.

7. ln a machine of the character scribed, a revolving platform, upright frame members rigidly secured to and'r\.: tendingl lengthwise of said platform near the .respecweasel -tive `lateral et ges thereof, connecting inemspective latmal edges thereof, an inclined boom arm comprising substantially parallel members rigidly connected oneto the other and spaced apart a distance less than the distancebetween said frame members, and forwardly converging connecting` members each rigidly connected at its respective ends` with one of said 'frai'ne members and one member of said boom arm. 1

9. In a machine of 4the character described, a revolving platform, apower plant and operating.mechanism mounted on said platform, longitudinally arranged plates rigidly secured to said platform and estending upwardly therefrom on the respective sides of said power'plant and operating mechanism, and an elongated structure conn prising.uprightplates rigidly connected one to'the other and rigidly secured to and supH ported wholly by the lirst mentioned plates.

l0. ln a. machine of the character described, a revolving platform, longitudinally arranged plates rigidly secured to said platform and ext-ending upwardly therefrom and arranged to form portions of the side valls of a housing mounted on said platform, an elongated structure comprising upright plates rigidly secured to and supported wholly by the first mentioned plates.

ll.. ln a machine of the character described, a platform, a housing mounted on said platform and comprising metal plates arranged on edge and rigidly secured to said platform, and other plates secured to the edges of the first mentioned plate and en* tending upwardly and forwardly therefrom to form an elongated structure supported by the first mentioned plates.

l2. ln a machine of the character described, a platform, and a unitary boom structure comprising apair of upright plates igidly secured at their lower edges to said platform and spaced one from the other, coi'inecting plates secured to the respective upright plates and converging forwardly therefrom, and a pair of elongated plates spaced relatively short distances apart and rigidly secured to the forward edges of said connecting plates.

f3. ln a machine of the character described, a platform, a pair of upright plates mounted on said platform, and spaced one from the other, a second pair of plates arranged in substantially vertical planes parallel one with the other and spaced apart a distance less than the distance Vbetween the nrs.Y mentioned plates, and connecting plates arranged obliqiiely to the first mentioned .ates and rigidly connected with'the respecplates ofthe'tirst mentioned pair and of the secondfpair of plates, to form a unitary snucture.

le. in an integralboom structure, a lower revolving frame portieri comprising upright plates spaced one from the other, and an outer .boom portion comprising vertical plates rigidly secured to the perspective first mentioned plates, saidboom port-ion being supported wholly by said frame portion and said Iboom portion converging from ysaid frameportion toward tl e outer end thereof.

l5. ln an'integralboom structure a lower frame `portion comprising upright frame mf prising substantially parallel'vertical plates, and converging vertical plates connecting vthe respective para-llel'fplateswith the corresponding frame -members l-G. ln an integ-ralboom structurea lower "rame portion `comprising upright plates 'igid y monnted'in spaced relation one tothe ote I rwardlyconverging plates rigidly i u to tlm-forward edges oftherespec tive frameplate, -a trainiversel plate ,arranged between and extending lengthwise of and rigidly sJcured at its respective edges to said converging plates, and substantially parallel plates rigidly secured to the forward edges of said converging plates and rigidly con nected one to the other.

17. ln an integral boom structure a lower frame portion comprising upright plates rigidly mounted in spaced relation onel to the other, forwardly converging plates rigidly secured to the forward edges of the respective frame plates, a transverse plate arranged between and extending lengthwise of and rigidly secured at its respective edges to said converging plates, and substantially parallel plates rigidly secured to the forward edges of said converging plates, and transverse plates arrzfmged between said parallel plates, rigidly coi iected at their respective edges tht-reto and arranged obliquely to the length of said parallel plates.

i8. In an integral boom structure a lower frame portion comprising upright plates rigidly mounted in spaced relation one to the other, and outer boom portion comprising parallel plates spaced a relatively short dis ance one from the other, and converging plates to connect the last mentioned parallel plates with the respective frame plates, and a top plate extending across said parallel plates to rigidly connect the same one to the other.

19. ln an integral boom structure a lower frame portion comprising upright plates rigidly mounted in spaced relation one to the nbers, and an outer vboom portion coml f llU other, an outer boom portion comprising parallel plates spaced a relatively short distance one from the other, and converging plates to connect the last mentioned parallel plates with the respective frame plates, and a single top plate rigidly secured to the upper et ges et said parallel plates and said converging plates.

2U. ln an integral boom structure a lower frame portion comprising upright plates rigidly mounted in spaced relation one to the other, an outer boom portion comprising parallel plates spaced a relatively short distance apart, and converging plates connecting said parallel plates with said frame plates, top and bottom plates secured respectively to the upper and lower edges of said parallel plates and said frame plates and extending' laterally beyond the edges of the respective upright plates, and upright brace hars extending between the respective outer edges of said top and bottom plates.

2l. ln an integral boom structure a lower trame portion comprising a pair of substantially triangular plates rigidly mounted in upright positions and spaced one from the other, forwardly converging plates rigidly secured at their rear edges to the forward edges of said triangular plates, and parallel plates rigidly secured to the forward edges of said converging plates and spaced a short distance one troni the other.

22. ln an integral boom structure a lower frame portion comprising a pair et' substantially triangular plates rigidly mounted in upright positions and spaced one Jfrom the other, forwardly converging plates rigidly secured at their rear edges to the forward edges of said triangular plates, parallel plates rigidly secured to the torward edges of said converging plates and spaced a short distance one from the other, the lower edge of said structure comprising a straight line. from the outer end thereof to the ii'orward edges of said triangular plates.

ln an integral boom structure a lower trarne portion comprising a pair of substantially triangular plates rigidly mounted in upright positions and spaced one iiroi'n the other, forwardly converging plates rigidly secured at their rear edges to the forward edges of said triangular plates, and parallel plates rigidly secured to the forward edges of said converging plates and spaced a short distanceI one from the other, the upper and lower edges of said converging plates and said parallel plates converging forwardly.

In testimony whereof, l aliix my sigi'lature hereto. Y

GRANT HOLE/H95. 

